The present invention relates to railway tank cars and, in particular, to manifolded tank cars which may be interconnected to accommodate loading or unloading of the entire group of interconnected cars without movement thereof from a single point and from either end of the train. In addition, individual ones of the tank cars may be loaded or unloaded from either end thereof, thereby accommodating consecutive loading, transporting and unloading of fluid ladings and facilitating the formation of unit trains.
The concept of providing fluid communication among a series of interconnected railway tank cars is disclosed in the prior art but previous systems have failed to provide an intertank connection arrangement which insured safe and convenient handling of the fluid ladings during transportation. For example, U.S. Pat. No. 1,542,116, issued to R. Welcker, discloses railway tank cars for interconnection in a manifolded arrangement to accommodate continuous emptying of the interconnected tanks from a single location without moving or disconnecting the cars. However, Welcker's arrangement does not provide for continuous loading of the interconnected tanks from a single location, and the intertank lading connections are along the longitudinal axes of the tanks which has been found to be a disadvantageous arrangement. Additionally, Welcker does not show a tank car which can be loaded or unloaded from either end thereof while providing the free vapor space or "outage" of the present invention. Furthermore, Welcker provides exposed valves for controlling the fluid lading flow, which valves must be individually manually operated.
U.S. Pat. No. 3,722,556, issued to William Jeffers et al., discloses a manifolded tank car arrangement which accommodates both loading and unloading of a string of interconnected tank cars from a single location, but Jeffers et al. provide the intertank lading connections at the bottoms of the tanks, and, in addition, they provide exposed and unprotected lading flow control valves, whereby to present a substantial safety hazard during transit of the tank car. Further, Jeffers et al. do not provide a lading conduit which, during loading, automatically determines the final outage of the lading in the tank and also accommodates loading and unloading from either end thereof, a combination of features which is critically necessary to save time in loading and unloading of unit tank trains and to accommodate certain bulk lading commodities which expand during transit.